non-attendance 
noun [mass noun]
Failure to attend or be present at a place where you are expected to be: pupils' non-attendance at school...
- Yet despite highly publicised anti-truancy initiatives - which have even included telephone hotlines urging the public to report truanting pupils - non-attendance still remains at crisis point.
- The President, Alexander, doesn't insist everyone attend, but non-attendance divides the camp.
- Often students were profoundly demotivated by their perception that many clinical teachers had a low level of commitment to teaching, and this led to a repetitive cycle of non-attendance by students and teachers alike.
- in the cart
- in the catbird seat
- in the cause of
- in the clear
- in the clouds
- in the club (or the pudding club)
- in the clutch
- in the cold light of day
- in the concrete
- in (the) course of ——
- in the dark
- in the dogbox
- in the driver's seat
- in the driving (or driver's) seat
- in the end
- in the event
- in the event of ——
- in the event that
- in the extreme
- in the family way
- in the field
- in the final (or last) analysis
- in the first (or second etc.) instance
- in the first place
- in the flesh